Actually MPG is determined by unused energy that is left in the emissions it
is a chemical analysis with factors of weight and other physics that overall
determines the MPG all this is done on a dyno. in a very controlled lab.
I used to know the formula (sorry be awhile since I worked in the lab)
the only way to truly achieve the listed MPG is with a lot of down hill
driving.


"General Schvantzkoph" > wrote in message
news
> When I bought my old Concorde in 94 the MPG ratings were pretty much spot
> on, the car got 22 in daily driving and 29 on long highway trips which is
> what the window sticker claimed. The MPG ratings for the new 300C is 17
> city/25 highway which isn't even close to the real values, I'm getting
> 15-16 in daily driving, just did a 220 mile round trip yesterday and it
> peaked at 20 MPG. The article on hybrids (quoted in another thread) also
> mentions that the real mileage is nowhere near the sticker values. So my
> questions are these, has the method for determining the MPG ratings for
> cars changed in the last 10 years? Have manufacturer's gotten better at
> gaming the system? How do they determine the MPG ratings? It's hard to see
> how Chrysler managed to come up with a 25 MPG highway rating on the 300C
> unless they did the test on a road that was down hill all the way.
>